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These scopes provide the best performance but may require more skill to master and appreciate. They have exceptionally fine optics and mechanics. Some are easy to use but are but on the large or heavy side. Some are intended for specialized uses. These scopes will appeal to the more technically inclined. Referring to the manual is highly recommended.

Looking for something to satisfy your appetite for power? Try a big Mak! For the most demanding enthusiast, our Orion 180mm Maksutov-Cassegrain Telescope sets a new standard for superb high-power performance in a remarkably compact design. With 7" of aperture and that long focal length Maksutov aficionados love, you'll get tack-sharp, high-contrast views and clearly defined photos with subtle detail.

The Orion 180mm Maksutov-Cassegrain (7.1") Maksutov-Cassegrain Telescope optical system has 2,700mm focal length (f/15). With 44% greater light grasp than a 150mm Mak, you'll get brighter images and better resolution. No other optical design can deliver such potent optical specifications in a package that measures just 22" long and weighs in at less than 16 lbs. The meniscus lens is fully multicoated for maximum light transmission, further enhancing image brightness. The visual back accepts 1.25" telescope eyepieces and accessories, and a dovetail bracket on the rear cell accepts any Orion finder telescope or EZ Finder. The dovetail rail on the underside of the tube attaches to your Orion SkyView Pro, Sirius, or Atlas mount.

Our biggest Mak offers the amazing image definition Maks are known for, but with a hefty 7" of aperture for brighter images.

Warranty

Limited Warranty against defects in materials or workmanship for one year from date of purchase. This warranty is for the benefit of the original retail purchaser only. For complete warranty details contact us at 800-676-1343.

Warning

Please note this product was not designed or intended by the manufacturer for use by a child 12 years of age or younger.

User level

Level 1 Beginner - Suited for a wide range of uses, these telescopes are simple to operate and set up. Some initial assembly may be required. Very good optical and mechanical quality. Great for families, young people, and folks who don't want to mess with equipment but just want to take a look. Any of these scopes will show you countless lunar craters, Saturn's rings and a myriad of star clusters and nebulas! Referring to the manual is recommended.

Level 2 Intermediate - These scopes offer higher performance and more advanced features than Level 1: Beginner models. They typically take a bit longer to learn and need some set-up or adjustments. But anyone with the slightest technical bent will have no problem getting familiar with these models. Referring to the manual is recommended.

Level 3 Advanced - These scopes provide the best performance but may require more skill to master and appreciate. They have exceptionally fine optics and mechanics. Some are easy to use but are but on the large or heavy side. Some are intended for specialized uses. These scopes will appeal to the more technically inclined. Referring to the manual is highly recommended.

Level 4 Expert - Expert telescopes offer uncompromising optical and mechanical quality for the most demanding amateur astronomer. They may be technically involved or designed for specialized use, such as astrophotography or detailed deep sky observation. They carry a premium price, but are designed to provide the ultimate performance in the field. Referring to the manual is highly recommended.

Optical design

Reflector telescopes use a pair of large and small mirrors to direct incoming light to the eyepiece.
Refractor telescopes refract, or "bend" incoming light to a focus by means of an objective lens.
Cassegrain telescopes, such as Maksutov-Cassegrains, "fold" incoming light using two mirrors and a front "corrector" lens.

Optical diameter

The optical diameter (also known as aperture), is the size of the telescope's main light collecting lens or mirror, measured in millimeters or inches. As the diameter increases, more light is collected and the resolution increases.

Focal length

The distance from the center of a curved mirror or lens at which parallel light rays converge to a single point. The focal length is an inherent specification of a mirror or lens and is one of the factors in determining resultant magnification for a telescope (along with the focal length of the eyepiece being used).

Focal ratio

The focal ratio of an optical system is the ratio of a telescope's focal length to its aperture. Short focal ratios (f/5, f/4.5) produce wide fields of view and small image scales, while long focal lengths produce narrower fields of views and larger image scales.

Resolving power

The theoretical resolving power of a telescope can be calculated with the following formula: Resolving power (in arc seconds) = 4.56 divided by aperture of telescope (in inches). In metric units, this is: Resolving power (in arc seconds) = 116 divided by aperture of telescope (in millimeters). Note that the formula is independent of the telescope type or model, and is based only upon the aperture of the telescope. So the larger the telescope's aperture, the more it is capable of resolving. This is important to keep in mind when observing astronomical objects which require high resolution for best viewing, such as planets and double stars. However, it is usually atmospheric seeing conditions (not the telescope) which limits the actual resolving power on a given night; rarely is resolution less than one arc-second possible from even the best viewing locations on Earth.

Lowest useful magnification

Lowest useful magnification is the power at which the exit pupil becomes 7mm in diameter. Powers below this can still be reached with the telescope to give wider fields of view, but the image no longer becomes brighter at a lower power. This is due to the fact that the exit pupil of the telescope (the beam of light exiting the eyepiece) is now larger than the average person's dark adapted pupil, and no more light can fit into the eye.

Highest useful magnification

The highest practical limit is different from the often used "highest theoretical magnification" specification. The "theoretical" limit generally is 50x the aperture of the scope in inches (2x the aperture in mm). So for example, an 80mm refractor is capable of 160x, and a 10" telescope is theoretically capable of 500x magnification.
But after approximately 300x, theory breaks down and real world problems take over. The atmosphere above us is constantly in motion, and it will distort the image seen through the telescope. This effect may not be noticeable at lower powers, but at higher powers the atmosphere will dramatically blur the object, reducing the quality of the image. On a good night (a night where the air above is steady and the stars aren't twinkling), the practical upper limit of a large telescope is 300x, even thought the theoretical limit may be much higher. This doesn't mean the scope will never be able to reach those higher "theoretical" powers - there will be that rare night where the atmosphere is perfectly still and the scope can be pushed past it's practical limit, but those nights will be few and far between.

Astro-imaging capability

The astro-photographic capability of the telescope is based on the style, stability, and accuracy of the mount and tripod. Telescopes on either very lightweight mounts or non tracking mounts (such as Dobsonians) are capable of only very short exposures such as lunar photographs. If a motor drive is attached to an equatorial mount, even a small lightweight mount is capable of capturing some planetary detail. Larger EQ mounts that utilize very precise tracking and excellent stability are capable of longer exposure deep-sky photography.

Warranty

This warranty gives you specific legal rights. It is not intended to remove or restrict your other legal rights under applicable local consumer law; your state or national statutory consumer rights governing the sale of consumer goods remain fully applicable.

Orders received by 1pm Eastern Time for in-stock items ship the same business day. Orders received after 1pm will ship the next business day. When an item is not in-stock we will ship it as soon as it becomes available. Typically in-stock items will ship first and backordered items will follow as soon as they are available. You have the option in check out to request that your order ship complete, if you'd prefer.

A per-item shipping charge (in addition to the standard shipping and handling charge) applies to this product due to its size and weight. This charge varies based on the shipping method.

Can I collimate a Schmidt-Cassegrain with a Collimating eyepiece?
Yes. If you use a star diagonal with your telescope, as is common for Schmidt-Cassegrain telescopes, remove it before inserting the Collimating Eyepiece. The eyepiece should be inserted to a depth such that the bottom edge of the eyepiece tube appears slightly wider than the outer edge of the secondary mirror when you look through the sight hole. Tighten the thumbscrew on the focuser tube to secure the Collimating Eyepiece in place. Now, you are ready to proceed with collimation.

Collimation is best performed using a “star test,” but reasonable collimation can be achieved with the collimating Eyepiece. There is only one collimation adjustment for Schmidt-Cassegrains: the tilt of the secondary mirror. Insert the Collimating Eyepiece directly into the visual back of the telescope. The shadow of the secondary mirror will appear as a dark circle near the middle of the field-of-view. Adjust the three Allen-head screws located in the center of the front corrector plate to center the secondary mirror on the crosshairs. Do not loosen the screws more than two turns, or the secondary mirror could fall off its mount! Even a 1/10th turn will generate a lot of movement. Likewise, do not adjust the screw in the middle of the secondary mirror cell. It holds the mirror in place. Final fine-tuning of collimation on reflectors or Schmidt-Cassegrains can be done with a “star test” using a high-power eyepiece. The collimating eyepiece is a preferred tool for Schmidt-Cassegrain collimation.

Can the Laser Collimator be used on Schmidt-Cassegrains and Maksutov Cassegrains?
No. The Laser Collimator doesn’t reflect off the primary, so it won’t work to collimate the primary for a Schmidt-Cass or Mak-Cass. It can be used to collimate the secondary mirror for a Schmidt-Cass.

How do I align a finder scope?
Before you use the finder scope, it must be precisely aligned with the telescope so they both point to exactly the same spot. Alignment is easiest to do in daylight, rather than at night under the stars. First, insert a low power telescope eyepiece (a 25mm eyepiece will work great) into the telescope’s focuser. Then point the telescope at a discrete object such as the top of a telephone pole or a street sign that is at least a quarter-mile away. Position the telescope so the target object appears in the very center of the field of view when you look into the eyepiece. Now look through the finder scope. Is the object centered on the finder scope’s crosshairs? If not, hopefully it will be visible somewhere in the field of view, so only small turns of the finder scope bracket’s alignment thumb screws will be needed. Otherwise you’ll have to make larger turns to the alignment thumb screws to redirect the aim of the finder scope. Use the alignment thumb screws to center the object on the crosshairs of the finder scope. Then look again into the telescope’s eyepiece and see if it is still centered there too. If it isn’t, repeat the entire process, making sure not to move the telescope while adjusting the alignment of the finder scope. Finder scopes can come out of alignment during transport or when removed from the telescope, so check its alignment before each observing session.
Can the finder scope crosshairs be adjusted?
Yes, but before taking this on, regardless of the orientation, the intersection of the crosshairs marks the center and that’s what important. However, should you feel the need to change the orientation of the finder scope’s crosshairs; you can do so by carefully rotating the finder scope in its bracket. Loosen the adjustment screws or pull on the tensioner (depending on the model) and rotate the finder scope tube in the bracket until the crosshairs are oriented the way you want. You should not need to rotate the finder scope tube more than 1/4 of a turn. .

For right-angle finder scopes, unthread the eyepiece to re-orient the crosshairs; gently turn the eyepiece until the crosshairs are oriented as you wish. You should not need to rotate the eyepiece more than 1/4 of a turn to do this. This may leave you with a loose eyepiece. If so, you can add an o-ring or shim to tighten it at the new orientation.
How do I calculate the magnification (power) of a telescope?
To calculate the magnification, or power, of a telescope with an eyepiece, simply divide the focal length of the telescope by the focal length of the eyepiece. Magnification = telescope focal length ÷ eyepiece focal length. For example, the Orion Apex 127mm Maksutov Telescope, which has a focal length of 1540mm, used in combination with the supplied 25mm eyepiece, yields a power of: 1540 ÷ 25 = 62x.

It is desirable to have a range of telescope eyepieces of different focal lengths to allow viewing over a range of magnifications. It is not uncommon for an observer to own five or more eyepieces. Orion offers many different eyepieces of varying focal lengths.

Every telescope has a theoretical limit of power of about 50x per inch of aperture (i.e. 254x for the Orion Apex 127mm). Atmospheric conditions will limit the usefullness of magnification and cause views to become blurred. Claims of higher power by some telescope manufacturers are a misleading advertising gimmick and should be dismissed. Keep in mind that at higher powers, an image will always be dimmer and less sharp (this is a fundamental law of optics). With every doubling of magnification you lose half the image brightness and three-fourths of the image sharpness. The steadiness of the air (the “seeing”) can also limit how much magnification an image can tolerate. Always start viewing with your lowest-power (longest focal length) eyepiece in the telescope. It’s best to begin observing with the lowest-power eyepiece, because it will typically provide the widest true field of view, which will make finding and centering objects much easier After you have located and centered an object, you can try switching to a higher-power eyepiece to ferret out more detail, if atmospheric conditions permit. If the image you see is not crisp and steady, reduce the magnification by switching to a longer focal length eyepiece. As a general rule, a small but well-resolved image will show more detail and provide a more enjoyable view than a dim and fuzzy, over-magnified image.
What are practical focal lengths to have for eyepieces for my telescope?
To determine what telescope eyepieces you need to get powers in a particular range with your telescope, see our Learning Center article: How to choose Telescope Eyepieces

Why do Orion telescopes have less power than the telescope at department stores?
Advertising claims for high magnification of 400X, 600X, etc., are very misleading. The practical limit is 50X per inch of aperture, or 120X for a typical 60mm telescope. Higher powers are useless, and serve only to fool the unwary into thinking that magnification is somehow related to quality of performance. It is not.
What is the best telescope for a beginner?
The “best scope” for anyone is highly subjective and varies based on the person who will be using the telescope. Their level of interest in the hobby, their aptitude for “the technical”, the level of investment that you want to make, and the ability to carry differing weights. For more detailed information on this topic see our Learning Center article: How to Choose a Telescope

How do I see the best detail on the surface of the Moon?
The Moon, with its rocky, cratered surface, is one of the easiest and most interesting subjects to observe with your telescope. The myriad craters, rilles, and jagged mountain formations offer endless fascination. The best time to observe the Moon is during a partial phase, that is, when the Moon is not full. During partial phases, shadows cast by crater walls and mountain peaks along the border between the dark and light portions of the lunar disk highlight the surface relief. A full Moon is too bright and devoid of surface shadows to yield a pleasing view. Try using an Orion Moon filter to dim the Moon when it is too bright; it simply threads onto the bottom of the eyepiece, you’ll see much more detail.
What will the planets look like through the telescope?
The planets don’t stay put like stars do (they don’t have fixed R.A. and Dec. coordinates), so you will need to refer to the Orion Star Chart on our website. Venus, Mars, Jupiter, and Saturn are among the brightest objects in the sky after the Sun and the Moon. All four of these planets are not normally visible in the sky at one time, but chances are one or two of them will be.

JUPITER: The largest planetJupiter, is a great subject to observe. You can see the disk of the giant planet and watch the ever-changing positions of its four largest moons, Io, Callisto, Europa, and Ganymede. If atmospheric conditions are good, you may be able to resolve thin cloud bands on the planet’s disk.

SATURN: The ringed planet is a breathtaking sight when it is well positioned. The tilt angle of the rings varies over a period of many years; sometimes they are seen edge-on, while at other times they are broadside and look like giant “ears” on each side of Saturn’s disk. A steady atmosphere (good seeing) is necessary for a good view. You may probably see a tiny, bright “star” close by; that’s Saturn’s brightest moon, Titan.

VENUS: At its brightest, Venus is the most luminous object in the sky, excluding the Sun and the Moon. It is so bright that sometimes it is visible to the naked eye during full daylight! Ironically, Venus appears as a thin crescent, not a full disk, when at its peak brightness. Because it is so close to the Sun, it never wanders too far from the morning or evening horizon. No surface markings can be seen on Venus, which is always shrouded in dense clouds. Sometimes using a color filter will lessen the glare of Venus and help you see the crescent.

MARS: If atmospheric conditions are good, you may be able to see some subtle surface detail on the Red Planet, possibly even the polar ice cap. Mars makes a close approach to Earth every two years; during those approaches its disk is larger and thus more favorable for viewing. For more detailed information on this topic see our Learning Center article: What Will You See Through a Telescope

What will a star look like through a telescope?
Stars will appear like twinkling points of light in the telescope. Even the largest telescopes cannot magnify stars to appear as anything more than points of light. You can, however, enjoy the different colors of the stars and locate many pretty double and multiple stars. The famous “Double-Double” in the constellation Lyra and the gorgeous two-color double star Albireo in Cygnus are favorites. Defocusing the image of a star slightly can help bring out its color. For more detailed information on this topic see our Learning Center article: Stars and Deep Sky Objects
What eyepiece should I use for terrestrial viewing?
For land viewing, it’s best to stick with low power eyepieces that yield a magnification under 100x. At higher powers, images rapidly lose sharpness and clarity due to “heat waves” caused by Sun-heated air. Remember to aim well clear of the Sun, unless the front of the telescope is fitted with a professionally made solar filter and the finder scope is removed or covered with foil or some other completely opaque material. Many Orion telescopes are capable of focusing on objects that are quite close, so you can view fine details of objects that are nearby. Try focusing on a flower or insect at close distance to enter a normally unseen microscopic world. Check the specifications on the product web page or instruction manual for your Orion scope.

Observing hint: If the object is too close to focus. You may be able to use an extension tube that allows the eyepiece to move further back as you focus closer. Try lifting the eyepiece out of the holder as you look. If it focuses in about an inch or two, you can purchase an eyepiece extension tube. For more detailed information on this topic see our Learning Center article: Choosing Eyepieces

How do I clean any of the optical lenses?
Any quality optical lens cleaning tissue and optical lens cleaning fluid specifically designed for multi-coated optics can be used to clean the exposed lenses of your eyepieces or finder scope. Never use regular glass cleaner or cleaning fluid designed for eyeglasses. Before cleaning with fluid and tissue, blow any loose particles off the lens with a blower bulb or compressed air. Then apply some cleaning fluid to a tissue, never directly on the optics. Wipe the lens gently in a circular motion, then remove any excess fluid with a fresh lens tissue. Oily finger-prints and smudges may be removed using this method. Use caution; rubbing too hard may scratch the lens. On larger lenses, clean only a small area at a time, using a fresh lens tissue on each area. Never reuse tissues.

How do I Clean a Mak-Cass Lens?
Any quality optical lens cleaning tissue and optical lens cleaning fluid specifically designed for multi-coated optics can be used to clean the Apex’s front meniscus lens or exposed lenses of your eyepieces or finder scope. Never use regular glass cleaner or cleaning fluid designed for eyeglasses. Before cleaning with fluid and tissue, however, blow any loose particles off the lens with a blower bulb or compressed air. Then apply some cleaning fluid to a tissue, never directly on the optics. Wipe the lens gently in a circular motion, then remove any excess fluid with a fresh lens tissue. Oily fingerprints and smudges may be removed using this method. Use caution; rubbing too hard may scratch the lens. For the large surface of the meniscus lens, clean only a small area at a time, using a fresh lens tissue on each area. Never reuse tissues.

How do I focus my Mak-Cass?
Point the telescope so the front end is aimed in the general direction of an object you wish to view. When you first look in the eyepiece, the image you see may be fuzzy, or out of focus. If so, gently turn the focus knob with your fingers until the image becomes sharp. Go a little bit beyond sharp focus until the image just starts to blur again, then reverse the rotation of the knob, just to make sure you’ve hit the exact focus point. You will have to readjust the focus when aiming at subjects of varying distances for daytime viewing, or after changing eyepieces. If you have trouble focusing, rotate the focus knob counter-clockwise as far as it will go. Now look through the eyepiece while slowly rotating the focus knob clockwise. You should soon see the point at which focus is reached.

Hint: Telescopes with long focal lengths and lots of focus travel can be challenging to focus. Turn the focus knob gently and allow the turn to settle before adjusting further.
How do I do astro photography with an Apex Scope?
When coupled to a SLR camera, the Apex becomes a telephoto lens. For terrestrial or astronomical photography, you need only a T-ring for your specific camera model. The T-ring attaches to your camera and threads onto the Apex’s eyepiece adapter. Use the camera’s viewfinder to frame the picture. Use the telescope’s focuser to focus the image. You may want to consider using a remote shutter release instead of the shutter release on the camera; touching the camera can vibrate the system and blur the resulting photographic image on the film. Also, be sure to use a solid tripod. If you would like to change the orientation of the camera relative to the telescope, do so by first loosening the knurled ring located in front of the eyepiece adapter You can then rotate the camera (and eyepiece adapter) to the desired orientation. Retighten the knurled ring when done. Add a Universal Camera Adapter and you can shoot through the eyepiece for a magnified picture of planets.

Are there optical performance differences between the Apex and StarMax models?
The optical tube of the Apex and StarMax are identical. The Apex is optimized for daytime terrestrial use and the StarMax for astronomical viewing due to the Equatorial mount included with the StarMax models.
I recently purchased a solar filter for my telescope and can’t see anything with it. Any suggestions?
One of the problems with a solar filter on a telescope is that it’s a bit tricky to aim it at the sun. You can’t look through the finder to point the scope or you’ll cause injury to your eye. So, cap off or remove the finder. Also, because with the very dark filter on the front if the sun is slightly outside the field of view of the eyepiece you’ll see pitch blackness in the field. With the solar filter properly mounted, try looking at the shadow of the optical tube on the ground, move the tube until the shadow is at a minimum. You’ll be pointed at the sun, or at least close enough to find it with a little sweeping and a low-power eyepiece to bring it into view. It can be difficult, even with the shadow method. An other trick to try after you’ve got it close with the shadow if your still not having any luck getting the sun in the field...take the eyepiece out of the focuser. Then look into the focuser...you won’t see an image but when the sun gets close you’ll see a flicker of brightness coming through the mirrors. Then pop the eyepiece back in and you should have it.

The Orion SkyView Pro 180mm Maksutov Cassegrain telescope allows you to view planets, close double-stars, clusters, and well-defined deep-sky targets. Add an optional GoTo kit at any time for computerized pointing with the push of a button.

This rugged padded Orion case is made specifically for carrying and protecting your 180mm Mak-Cass Optical Tube. It is made from heavy water-resistant material and has three zippered accessory pockets as well as a convenient shoulder strap.

The 1.25" dielectric mirror star diagonal angles the eyepiece to a comfortable viewing position, while dielectric coatings give you brighter images compared to a standard star diagonal. The harder surface from the coatings also makes cleaning easier.

For producing striking, high-contrast color CCD astrophotography of emission nebulae with a monochrome CCD camera, you should use extra-narrowband filters. The 1.25" Orion Extra-Narrowband Hydrogen-Alpha filter is one of a set of three filters.

Have you wanted to view the Horsehead, California, and Cocoon nebulas? This 1.25" Orion Hydrogen-Beta Nebula Telescope Filter blocks everything but the light these faint nebulas emit, providing the contrast needed for viewing these elusive nebulas.

For producing striking, high-contrast color CCD astrophotography of emission nebulae with a monochrome CCD camera, you should use extra-narrowband filters. The 1.25" Orion Extra-Narrowband Oxygen-III filter is one of a set of three filters.

For producing striking, high-contrast color CCD astrophotography of emission nebulae with a monochrome CCD camera, you should use extra-narrowband filters. The 1.25" Orion Extra-Narrowband Sulfur-II filter is one of a set of three narrowband filters.

Would you like more contrast and less glare while viewing the moon and bright planets? The 1.25" Orion Variable Polarizing Telescope Filter reduces both and brings out details. And you can adjust the amount of light transmission for the perfect view.

This set of Edge-On Planetary telescope Eyepieces is designed for exceptional planetary and lunar views. Included are the 5mm, 9mm and 14.5mm telescope eyepieces. All have a flat-field design which means sharp focus to the edge of the viewing field.

This mighty 5x Barlow will easily meet the magnification demands of any telescope system. The Orion High-Power 5x 4-Element Barlow Lens quintuples the power of any 1.25" telescope eyepiece, providing far more magnification than a 2x or 3x Barlow.

A great tool for bringing out details in the planets and Moon is this 1.25" set of four Orion Color Telescope Filters. Each colored filter brings out different details in the planets allowing for a totally different view.

This set of Orion Expanse telescope eyepieces is perfect for those that want huge views of the sky. Included are the 6mm, 9mm, 15mm, and 20mm telescope eyepieces. All are fully coated for bright high contrast images.

Need for a good way to start identifying constellations? The Orion Star Target Planisphere is the perfect telescope accessory! Designed for 30-50 deg North latitude and includes simple instructions and viewing tips. Just dial in the date and time!

If you are an avid astronomer you know that you should always use red light instead of white to help protet your night vision. The Orion RedBeam II LED Flashlight has adjustable brightness which lets you observe without ruining your night vision.

At Orion, we are committed to sharing our knowledge and passion for astronomy and astrophotography with the amateur astronomy community. Visit the Orion Community Center for in-depth information on telescopes, binoculars, and astrophotography. You can find astrophotography "how to" tips and share your best astronomy pictures here. Submit astronomy articles, events, and reviews, and even become a featured Orion customer!